Area Forecast Discussion
Issued by NWS Austin/San Antonio, TX

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FXUS64 KEWX 261833
AFDEWX

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
133 PM CDT THU MAY 26 2016

.AVIATION...
All sites have gone to VFR except KSAT which is still hanging onto
MVFR. They too should go above 3kft shortly. Very moist and
unstable atmosphere this afternoon so went with VCTS for all areas
from the afternoon hours until the late evening. Models are still
inconsistent on when and where the convection will fire so until
storms are threatening the TAF sites, will go with the Vicinity
wording. MVFR/IFR ceilings should return overnight. The wildcard
will be whether or not a larger system will develop overnight and
clear the area by Friday morning. This is still a fairly low
probability event at this time but something to consider on how
that will affect the precip chances and clouds early Friday AM.
Will likely have a repeat of scattered convection on Friday
afternoon.

&&

.PREV DISCUSSION... /ISSUED 1105 AM CDT THU MAY 26 2016/

UPDATE...
A mid level impulse is moving east across the Edwards Plateau late
this morning. Most rains were over Central Texas and have lowered
pops most areas, except for our northeastern areas. Skies have
cleared over most of the Rio Grande Valley. This will allow solar
heating to enable convective temperatures to be reached. Showers
and thunderstorms should develop this afternoon. However, a
capping inversion may inhibit some development. CAPE of up 4000
j/kg and 0-6 km shear of up to 30 kts will allow for some strong
to severe storms. PWS have climbed to near 2 inches making locally
heavy rains and some flooding possible. The remainder of South
Central Texas forecast is on track.

PREV DISCUSSION... /ISSUED 640 AM CDT THU MAY 26 2016/

AVIATION...
Isolated to scattered convection has developed north of Austin and
will mention VCTS in the TAFAUS for the morning hours and VCSH
for the San Antonio sites. MVFR/IFR ceilings are in place this
morning and these should hold until around noon. Should see a
break in rain chances in the early afternoon hours before
additional storms are likely in the late afternoon and evening
hours. Will cover this threat with VCTS for now. Another round of
MVFR or IFR ceilings can be expected tonight.

PREV DISCUSSION... /ISSUED 350 AM CDT THU MAY 26 2016/

SHORT TERM (Today through Friday)...
Upper air analysis last evening showed a trough from the Great
Basin to southern CA with west-southwesterly flow over Texas. This
was bringing mid-level moisture from the Pacific across Mexico. At
the surface, there was a dryline over west Texas and east of this
feature winds were from the southeast across our CWA. Dewpoint
temperatures were in the mid to upper 70s. During this period the
upper level trough will move from the southwest into the central
plains with the trough axis moving into central Texas by the end
of the period. The low level flow will continue to be from the
southeast today and tonight. PW values will increase to around two
inches over the southeastern part of the CWA this afternoon. This
looks to be the favored location for showers and thunderstorms
this afternoon. With PW that high, locally heavy rain is possible.
Thursday evening a shortwave trough will move through the pattern
and initiate thunderstorms near the dryline. These storms will
develop over our northwestern area and move toward the southeast
into a moisture rich atmosphere. Locally heavy rain will continue
to be possible. In addition, convective parameters suggest
possible severe thunderstorms over the western 2/3 of the area with
CAPE 2000-3000 j/kg, deep layer wind shear 30-40 kts, and steep
mid-level lapse rates. Large hail and damaging wind gusts are the
most likely threat with isolated tornadoes possible. Friday the
dryline will move through the western half of the area. Expect
that thunderstorm development will not happen until afternoon over
the eastern half of the CWA. Convective parameters are again
suggestive of severe storms over the eastern half of the area.
Damaging wind gusts and isolated tornadoes are the most likely
threats. Rainfall totals from this afternoon through Friday
afternoon will be one to three inches with isolated amounts up to
five inches possible.

LONG TERM (Friday Night through Wednesday)...
The upper level pattern will become zonal Friday night as the
trough moves away to the northeast. This pattern will continue
through the weekend and the early part of next week. The low level
flow will remain mostly from the southeast keeping moisture high
in the boundary layer. This will keep the atmosphere conditionally
unstable and allow weak perturbations in the mid to upper flow to
produce thunderstorms. Will carry slight to low end chance POPs
each day. The reality is most places will be dry, but there will
likely be some convection each day. Models do not suggest any
organized systems through the long term.

&&

.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry              84  73  85  73  90 /  70  60  60  30  30
Austin Bergstrom Intl Airport  84  73  85  72  89 /  70  60  60  30  30
New Braunfels Muni Airport     86  73  87  72  88 /  70  50  60  20  30
Burnet Muni Airport            84  71  85  71  88 /  70  60  60  30  30
Del Rio Intl Airport           90  72  95  71  90 /  40  60  10  10  40
Georgetown Muni Airport        82  72  84  72  89 /  70  60  60  30  30
Hondo Muni Airport             87  73  91  73  90 /  60  60  30  20  30
San Marcos Muni Airport        86  73  86  72  88 /  70  50  60  20  30
La Grange - Fayette Regional   84  75  85  75  88 /  70  50  70  30  30
San Antonio Intl Airport       86  74  87  74  88 /  70  60  40  20  30
Stinson Muni Airport           87  75  90  75  90 /  70  60  40  20  30

&&

.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

Mesoscale/Aviation...09
Synoptic/Grids...04
Public Service/Data Collection...33



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